Landscape \\\ Adjacent Landscape Level \\\ Manual editing

I created a 7x7 map project where I manually painted over 28 tiles of height map.
I now know that we can ‘‘weld’’ the Landscape by creating a new adjacent map using the function in the picture below.

That not what I have done and now, I can not find a way to tell Unreal that my individually created map need to be connected.

Tell me, is there a way to hook this up?